Fibrous sheet material for producing dyes thereon by electrolytic oxidation



Patented Nov. 4, 1947 FIBROUS SHEET MATERIAL FOR PRODUC- ING DYESTHEREON BY ELECTROLYTIC OXIDATION Myer Solomon, deceased, late ofWestmont, N. J.,

by Nellie W. Solomon, administratrix, Princeton, N. J., assignor toRadio Corporation of America, a corporation of Delaware No Drawing.Application December 23, 1942, Serial No. 469,959

5 Claims. I

This invention relates to the electrolytic formation of quinoneiminedyes, particularly in connection with facsimile recording.

Various different types of facsimile receivers are used at the presenttime, and these are referred to in the copending application Serial No.178,743, filed December 8, 1937, now U. S. P. 2,306,471, grantedDecember 29, 1942, of which the present application is acontinuation-in-part. Attention is directed to the rsum of the prior artgiven in said patent over which the present application constitutes animprovement.

In the present invention, it is proposed to produce the picture orprinted matter on the recording paper in the form of a quinoneimine dye,the amount of such dye deposited being a function of the amount ofcurrent caused to flow through the recording paper. When the image is soformed, the pressure of the printer bar is maintained constant and theamount of current which is passed through increments of the paper isvaried in accordance with the light and dark portions present on thepicture or printed matter being scanned at the facsimile transmitter.When dyes are so formed by electrolytic action, varying half tone shadesmay be produced by merely regulating the amount of the current which iscaused to flow through the recording paper.

In the present invention, facsimile recording is accompanied byelectrolytic oxidation or forming quinoneimine dyes by electrolyticallyoxidizing chemicals that react to produce such dyes when oxidized.

The principle of operation of the present invention resides broadly inthe fact that certain compounds or solutions produce quinoneimine dyeswhen oxidized. When any neutral, mildly acid, or mildly alkalineelectrolyte is subjected to an electric current, acidification andoxidation are brought about at the positive electrode while theelectrolyte is alkalized and reduced atthe negative electrode. Suchoxidation is attributable to the nascent oxygen available at thepositive electrode while the electrolyzing current is flowing. Whenthere is present in the electrolyte, under these circumstances,compounds capable of oxidizing and coupling, such as, an aromaticparadiamine and an aromatic compound having an unsubstituted ringposition para to an amino or hydroxyl group, quinoneimine dyes areformed.

It is accordingly an object of the present invention to formquinoneimine dyes by electrolytic oxidation of certain compounds.

Another purpose of the present invention resides in the formation ofquinoneimine dyes by passing an electric current through a solutionwhereby the solution may be oxidized at the positive electrode toproduce such a dye.

A further object of the present invention is a fibrous sheet materialcarrying an electrolyte and components capable of forming quinoneiminedyes by electrolytic oxidation.

Other purposes and advantages of the present invention will becomeapparent to those skilled in the art from the following more specificdescription of the present invention.

The essential components of the composition applied to the carrier whichis a fibrous sheet, film, foil or the like, are the electrolyte and thecomponents which are oxidized to produce the desired dyestuff. As theelectrolyte, sodium chloride is preferred. This compound is generallyused in a quantity such that a liter of solution will contain sodiumions equal to .1 to 3 gram molecular weights. Preferably, however, theconcentration of sodium ions is about 1 gram molecular weight per liter.In lieu of sodium chloride there may be used other neutral electrolytessuch as sodium bromide, potassium bromide, potassium chloride, lithiumchloride, barium chloride, calcium chloride, magnesium chloride,potassium sulfate, sodium sulfate, magnesium sulfate and the like.

It is obvious that various appropriate chemicals may be added to deepenthe color or to improve the background permanency. The substitution ofbarium (and sometimes calcium) chloride for part or all of the sodiumchloride makes the colors more blue in shade and faster to washing, butsuch substitution usually lowers the solubility of the dye chemicals andnot infrequently causes the formation of sludges which are of courseobjectionable. of iron, chromium, or other metals sometimes improve thefastness of the dye to washing and deepen the shade, or even change thecolor, of the dye. The addition of tartrates, formates, sulphites,hydrosulphites, thiosulphites, and/or other reducing agents results in aretardation of the background darkening, and in an extension of theuseful working life of the solution by preventing slow chemical changesduring storage, but is sometimes objectionable inasmuch as such reducingagents tend to decrease the sharpness of the detail of the recordings,to weaken the color of the dyes formed, and to require more electriccurrent to produce the color.

The following example illustrates the forma- Complex cyanides tion ofquinoneimine dyes in electrolytic facsimile recording:

EXAMPLE Quznonimine dyes (union of two dye intermediates by oxidation)Ingredients Formula gggilt Grains (I)paramincdimethylanilinehydrochloride NH: N(CHa)2'HC1 3. 46

NHr-HCI (II) metaphenylenediaminedihydrochloride. 3. 62

NHs-HCI (III) common salt NaOl- 68. 47 (IV) Water to a total volume ofone liter.

The ingredients are dissolved in water, giving a pale yellow solution.With a copper-containing positive electrode deep greenish-bluerecordings on a white background are obtained, the color appearing onboth sides of the sheet. With a steel positive electrode the color isweaker, and in a few minutes fades out to a still weaker shade. N orecordings have been obtained with platinum, platinum-iridium, ortungsten electrodes. On standing for several days, the copper-producedrecorded areas darken to blue-black, and the background also darkens.This darkening is greatly reduced, but not eliminated, by washing therecordings with water within a few hours of their formation. Thereaction is general in scope,

as ingredient (I) may be replaced by other paradiamines or by para-aminophenols, and ingredient (II) may be replaced by other aromatic compoundshaving an unsubstituted ring position para to an amino or hydroxy group.Among the chemicals that have given this type of facsimile recordingare:

Ingredient I p-Aminodimethylaniline p-Arninodiethylanilinep-Phenylenediamine p-Aminodiphenylamine p-Aminodiphenylamine sulphonicacid p-Aminophenyl-p-tolylamino sulphonic acid Ingredient IIm-Phenylenediamine Alpha naphthylamine Alpha naphthol Gamma acid Chicagoacid S-hydroxyquinoline GENERAL DISCUSSION In any of the above mentionedexamples it will be noticed that the electrodes per so do not play anypart in the formation of the dye other than as a means for subjectingthe solution to an electric current, or as in the case of some oxidationdyes, where they may act as catalysts. The metal or material of whichthe electrodes are made does not combine with the solutions or chemicalsand does not enter into the composition of the electrolytically produceddyes. The electrodes may, in' some instances, prevent the formation ofthe dye as stated above and by selecting a metal which will prevent dyeformation for one of the electrodes the dye may be permitted to form onone side of the paper and trodes frequently is of particular advantagewhere alternating current is applied to the electrodes, or where theunrecorded side of a facsimile recording is to be used for a subsequentrecording.

By the use of any of the above mentioned solutions and compounds, it ispossible to produce dyes and pigments by subjecting solutions ormixtures of'chemicals to an electric current. Such dyes or pigments maythen be collected in a paste, powder or liquid form and subsequentlyused for coloring paints, inks, etc. or for dyeing various materials.Also, materials such as clothing, piece goods, yarn, etc., may be dyedby immersing such material in a container which has been filled with thesolutions and subsequently subjecting the entire mixture to the flow ofan electric current in order that the dyes may be fixed in the materialsso immersed. This method produces a uniform coloring of the material,particularly when some agitation is present during the time that theelectrical current is applied to the solution.

If it is desired that not all of the material be subjected to theelectrical current in order that varying intensities of colors may beproduced, or that designs or other patterns be printed on the material,it is obvious from the above that only portions'of the material, allofwhich has been treated with the proper chemicals, need be subjected tothe electric current and such selectivity of activation may beaccomplished by controlling the distribution of current to variousportions of the material either by controlling the current per se or byapplying a non-conducting material such as varnish, lacquer, parafiin,etc., to the material where it is desired that no current'shall pass andno color shall be present. Furthermore, the material may be passedbetween a pair of rollers which are to act aS electrodes of an electriccircuit and wherein one or both of the rollers is recessed or engravedor otherwise altered in contour or provided with non-electricallyconductive areas in order that only portions of the material passingbetween the rollers will be subjected to the passage of current.

It is to be understood that,'although the present invention is concernedprimarily with the reproduction of printed matter, pictures, etc, by afacsimile system, the invention may well be applied to other fields, andin' combination with other methods of dye formation.

Furthermore, it is to be understood that the invention, when applied toa facsimile receiver, may be used in such a mannerasto produce acontinuous process wherein the paper to be 5. printed is fed from a'rolland passed through the solution in order to .sensitize the same. Thepaper so sensitized may then be directly transferred or fed to thefacsimile receiver at which point the electric current causes thesolution contained in the paper. to be changed into dyes in accordancewith the values of the electric current. If desired, after passsingthrough the facsimile receiver, the paper may or may not beautomatically or otherwise exposed to light and/or directed to a fixingbath and subsequently washed in order to reduce the tendency for thebackground to discolor. After the paper has been washed it may then bepassed automatically or otherwise to a dryer at which point thefacsimile reproduction is completed and ready for perusal and storage.

It is also to be understood that sheets of paper or material may beimpregnated with one or another of the various solutions and the paperpermitted to be subsequently dried. When the paper is dry it isrelatively non-conducting and is not in a proper condition to beoperated upon by the passage of electric current, The paper may then behumidified or dampened by any appropriate means, such as by steam orwater vapor, for instance, in order to increase the conductivity thereofand the paper may then be placed in the facsimile receiving machine foruse. By so preparing separate sheets of paper or separate rolls of paperit is possible to use the sensitized paper by merely subjecting the sameto a certain degree of moisture in order that the current may passtherethrough and accordingly cause a dye to appear on the paper.

It is also to be understood that paper, cloth, or other materials onwhich dyes are to be produced electrolytically may be subjected in wholeor in part to any number of successive chemical treatments, and electriccurrent applied to all or part of the treated material before, during,or after any stage or stages of the treating process, in order toproduce various multicolor effects.

It is also to be understood that the term facsimile as used herein isintended to involve not only the reproduction on the recording materialof a pre-existing subject, for example a photograph which is scanned andreproduced in accordance with the impulses emanating from the scanningoperation, but also embraces the recording of subject matter in theprocess of creation or formation without a, physically pro-existingsubject. As illustrative of this latter category would bethe recordingof simply a mental preconception, for example a pattern or design,either of a single color and shades thereof, or multicolors, which isrecorded in accordance with an appropriate manual or automatic variationof the electric impulses delivered to the electrodes. Similarly in thiscategory is intended the recording of an arbitrary or haphazard design,pattern or other subject, for example one secured by haphazardly orarbitrarily varying electric impulses delivered to the electrode bypunching keys on a master keyboard having suitable electricalconnections, by manually or automatically varying resistance, or thelike.

Having described the invention, what is desired to be secured by LettersPatent is:

1. The method of electrolytically producing quinoneimine dyes on afibrous sheet material which comprises treating said sheet material withan aqueous solution containing a sufficient amount of a water-solubleinorganic salt as the electrolyte to facilitate the passage of theelectrolyzing current, and a sufficient amount of an aromaticpara-diamine and an aromatic compound having an unsubstituted ringposition para to a group selected from the class consisting of amino andhydroxyl groups to form a quinoneimine dye upon oxidation and eifectinganodic oxidation and coupling of said aromatic paradiamine and saidaromatic compound having the aforesaid unsubstituted ring position withthe attendant formation of a quinoneimine dye by subjecting said fibroussheet material to the action of an electrolyzing current.

2. The method of producing facsimile records on a fibrous sheet materialin response to electrical signal variations which comprises treating thefibrous sheet material with an aqueous solution containing a sufficientamount of a watersoluble inorganic salt as the electrolyte to facilitatethe passage of the electrolyzing current and a sufficient quantity of anaromatic para-diamine and an aromatic compound having an unsubstitutedring position para to a group selected from the class consisting ofamino and hydroxyl groups to form a quinoneimine dye upon oxidation, andeffecting anodic oxidation and coupling of said aromatic para-diamineand said aromatic compound having the aforesaid unsubstituted ringposition with attendant quinoneimine dyestufi formation by subjectingthe fibrous sheet material to the action of an electrolyzing currentapplied in accordance with the received signal variations.

3. The process as defined in claim 1 wherein the aromatic para-diamineis para-amino-dimethylaniline hydrochloride and wherein the aromaticcompound having an unsubstituted ring position para to a group selectedfrom the class consisting of amino and hydroxyl groups is meta-phenylenediamine hydrochloride.

4. The process as defined in claim 2 wherein the aromatic para-diamineis para-amino-dimethylaniline hydrochloride and wherein the aromaticcompound having an unsubstituted ring position para to a group selectedfrom the class consisting of amino and hydroxyl groups is meta-phenylenediamine hydrochloride.

5. A fibrous sheet material for the electrolytic formation ofquinoneimine dyestuffs carrying a composition capable of producingquinoneimine dyes by anodic oxidation when subjected to the action of anelectrolyzing current and containing as its essential components asufficient amount of a water soluble inorganic salt as the electrolyteto facilitate the passage of the electrolyzing current and a sufiicientquantity of p-amino-dimethylaniline hydrochloride and m-phenylenediamine hydrochloride to form a quinoneimine dye upon oxidation.

NELLIE W. SOLOMON, Administratria: of Estate of Myer Solomon, De-

ceased.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 168,466 Edison Oct. 5, 1875761,310 Loeb May 31, 1904 1,844,199 Bicknell et al Feb. 9, 19321,880,449 Hickmen et al Oct. 4, 1932 1,892,099 Cornell Dec. 27, 1932(Other references on following page) Number Red 14,824

Number Number 10 16,189 17,241 21,634 536,506 28,923

Name Date Basch -1- June 2, 1936 Weyde et a]. June 16, 1942 Albers eta1. Jan. 26, 1943 Green May 31, 1910 Fletcher July 7, 1914 FOREIGNPATENTS Country Date Great Britain 1907 Great Britain 1905 Great Britain1904 Germany Oct. 23, 1931 Netherlands 1 Feb. 15, 1933

